The present invention relates to the field of digital communications. In particular the present invention discloses a packet switched digital broadcast communication system for broadcasting digital data with privacy and access control features.
The Internet has become the standard system for allowing different computer systems communicate. The Internet consists of a global interconnection of computer networks that share a common suite of communication protocols. Specifically, all the computers on the Internet communicate using the Transport Control Protocol and the Internet Protocol (TCP/IP).
The very popular global Internet has made the well-known Transport Control Protocol and Internet Protocol (TCP/IP) into the de facto standard digital communication protocol. However, TCP/IP was originally designed for one to one, sender to receiver, communication. As the popularity of the Internet has gained, the data traffic load on the Internet has greatly increased. Due to the popularity of the Internet and its rapid growth, it is common to experience Internet xe2x80x9cBrown-outsxe2x80x9d caused by data traffic jams. To facilitate data communication, several methods of avoiding these data traffic jams have been devised.
One method of avoiding the problems is to create a private xe2x80x9cintranet.xe2x80x9d An intranet is a privately owned and used computer network that uses Internet protocols such as TCP/IP. Creating a private intranet is a very expensive proposition. Thus, the technique of creating private intranets to relieve traffic problems is only practical for cost insensitive projects.
It is well known that much of the traffic carried by the global Internet is redundant information. For example, millions of World Wide Web viewers access the same web pages and the same video streams from popular World Wide Web sites. For example, many people retrieve the same news information from the CNN interactive located at http://www.cnn.com/. Such popular World Wide Web sites therefore send the same web pages and the same video streams to the millions of World Wide Web viewers on individual unicast transport connections. All of these individual unicast streams create a large amount of redundant Internet traffic.
To help reduce data traffic jams caused by redundant information streams, a multicast protocol was created for the Internet. The Internet multicast protocol uses a single data stream to carry the same information to multiple recipients. Each new recipient xe2x80x9csubscribesxe2x80x9d to a desired multicast stream. When a new multicast protocol recipient subscribes to a multicast stream, the upstream routers that couple the recipient to the multicast stream begin routing a copy of the desired multicast stream to the network that the new recipient is attached to.
Internet multicasting promises to reduce Internet traffic by eliminating redundant information streams. However, there are several problems associated with Internet multicasting. One large problem is that Internet multicasting is currently not well supported by much of the current Internet infrastructure. For example, many of the older routers and switches on the Internet do not support multicast routing. Another problem with Internet multicasting is that there are very few quality-of-service guarantees for Internet traffic such that multicast streams are not guaranteed reliable service. Yet another problem with Internet multicasting is that there is no inherent data security or access control for multicast streams such that any entity can tap into and monitor Internet multicast streams.
Due to the above described and other problems associated with Internet multicasting, the popularity of Internet multicasting has been limited. Therefore, the number of software applications that support the Internet multicast protocol is limited. Although Internet multicast shows promise, it would be desirable to have improved methods of delivering Internet multicast information.
The present invention discloses a directed data broadcast system. The directed data broadcast system operates by accepting a plurality of data streams from a plurality of different data origination sources at a centralized data broadcast center. The data broadcast center processes the incoming data streams by encrypting, addressing, and multiplexing the data streams into a single combined data stream. The combined data stream is then modulated and broadcast on a broadcast medium such as radio frequency. A plurality of receiver systems receive the signal broadcast across the broadcast communication medium. Each receiver demodulates the broadcast signal to retrieve the combined data stream. The receiver then selects packets addressed for that particular receiver or a group to which the receiver belongs. The selected packets are decrypted and multicast on a LAN coupled to the receiver to deliver to an application.
Other objects, features, and advantages of present invention will be apparent from the company drawings and from the following detailed description.